Modifying PowerStore to include these fields in the product details page would probably be the best way to go about this. This is a little custom but it should not require any hand coding. You would want to add these fields to your order details table, then you can add the form fields to the to the add to cart form on the product details page.
Next you would need to update the cart using eCart to include these new columns for the requested data. Then on the confirm page you would want to update the store order details server behavior to and associate the newly added cart columns with the new columns in the order details table.
As you can see there are a few steps to the process but it is possible if you have eCart.